The invention relates to the field of the manufacture and the method of operation of vehicles and vehicle components. In particular, the invention relates to land vehicles for daily road traffic, in particular motor vehicles, such as, for example, commercial or utility vehicles. The terms commercial or utility vehicles are used interchangeably herein.
Vehicles in daily road traffic frequently travel temporarily in overrun conditions depending on the instantaneous speed, acceleration of the vehicle (positive or else negative, for example in the case of braking) or other external influences, such as interventions by the driver.
“Overrun conditions” herein refer to or mean the drag mode of the engine as a result of the kinetic energy of the vehicle which is fed in via the closed drivetrain. The vehicle, which at the time of an overrun condition has more kinetic energy than the engine is making available at that moment, drags the engine, i.e. attempts to accelerate it.
On a flat roadway, what are understood to be overrun conditions are possible only if the driver brakes the vehicle by taking his foot off the gas pedal. On a negative gradient, however, overrun conditions can occur for a relative long time either with a positive or negative vehicle acceleration or with a constant velocity depending on their degree and the driver's reaction at the gas pedal.
Overrun condition phases only make up a relatively small proportion of the entire travel time. In particular, it has not been previously possible to predict when overrun conditions will occur in a vehicle since the behavior of the driver has a significant influence on this. However, the driving behavior of the driver is not predictable, for which reason there is conventionally no possible way of predicting any possible overrun condition phases before they actually occur. The uncertainty in terms of the future or imminent driving behavior of the driver and therefore his vehicle prevents overrun condition phases which occur from being utilized in a technically efficient manner. Vehicle components can be controlled in a changed way only in the case of an overrun condition phase which has already commenced and is still continuing. However, conventionally, there is also uncertainty here about the duration for which an overrun condition phase, which has already commenced, will still continue since, apart from the driver's reaction, the future operating states of the vehicle, which are partially conditioned by the section of road, are unknown. This limits the possibilities of optimized control of vehicle components. Owing to the many unpredictable influences, there is not yet any way of overcoming the above-mentioned limitations with respect to the control and method of operation of vehicle components.
The object of the present invention is to make possible the advance identification of overrun condition phases in vehicles, in particular of land vehicles such as, for example, road vehicles.
The object is achieved by the present invention, which makes it possible for the first time to utilize cartographic altitude positions of a section of road, i.e. its local altitude coordinates (in the perpendicular direction with respect to the surface of the earth) technically in order to predict the occurrence of overrun condition phases of a mobile vehicle. Hitherto, navigations systems in mobile vehicles were used only to provide the driver with orientation in the two-dimensional road network and to calculate the shortest or the fastest route for the purpose of route planning. Altitude coordinates do not play a role in such navigation since the vehicle is tied to the respective road and must necessarily follow its altitude profile; only the horizontal coordinates parallel to the surface of the earth (in the positive y/x directions and in the North/South/East/West directions) are significant for the instantaneous position of the vehicle in the road network and for the resulting shortest route (the profile of which is correspondingly also represented only two-dimensionally). Conventionally, altitude coordinates are also not utilized in a technical manner to control a component of a vehicle, but rather exclusively for finding the route to a destination.
On the other hand, the invention permits an optimization of the operational sequence or of the control processes of the vehicle, in particular of a component of the vehicle, as a function of segments of a road section lying ahead of the vehicle, which segments have negative gradients. Conventionally, only the parameters of the actual vehicle which indicate the respective operating states of the vehicle components are used as influencing variables for controlling and optimizing them but not the cartographic data of a section of road being traveled on. The invention permits vertical position coordinates of the section of road and/or of the vehicle to be included in order to calculate in advance the future driving behavior of the vehicle and, in particular, calculate a prediction about overrun condition phases which are expected to occur. On the basis of said overrun condition phases it is possible to improve the control of one or more vehicle components.
It is therefore possible, for example, to identify in advance whether and when an overrun condition phase which continues for a relatively long time is imminent, during which phase a control process, switching process or other working step of a vehicle component can be carried out without consuming energy or with relatively low consumption of energy. While the imminent driving behavior of the driver is conventionally considered to be unpredictable, the present invention permits a qualitative technological advance in terms of the control and method of operation of vehicle components taking into account influencing variables which lie outside the vehicle itself. Any desired vehicle components, in particular components of road-bound vehicles, for example of commercial or utility vehicles, can benefit from this.
In particular, it becomes possible to identify overrun conditions or overrun condition phases in advance and to utilize them technically in the vehicle. In particular, phases in which the vehicle engine of the traveling vehicle receives, via its connection to the vehicle wheels, an additional torque which has the effect of increasing the engine speed can be utilized for energy-saving or energy-free execution of a control process, switching process or other working step of any desired vehicle component.
Other objects, advantages and novel features of the present invention will become apparent from the following detailed description of one or more preferred embodiments when considered in conjunction with the accompanying drawings.